Dual Phosphor Wheel Projection System Reduces Spoke Time
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Solution Overview
Problem
Laser Phosphor (LaPh) projection systems face issues such as quenching, limited ability to produce deeper reds, spoke time, and limited color cycles per video frame, due to the inefficiencies and limitations of phosphor materials and mechanical color wheels.
Innovation Solution
A dual phosphor wheel system using three blue lasers, one red laser, and independent, non-segmented phosphor wheels, where the first phosphor wheel emits yellow to orange light and the second phosphor wheel emits green to yellow light, supplemented by a red laser to enhance red light production and reduce thermal limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single phosphor wheel is used to convert blue laser light into red and green light, then the system structure is simplified, but color saturation is reduced and a color wheel must be added in cascade
Solution Approach 1:
The patent divides the single phosphor wheel into two separate phosphor wheels, each optimized for specific color ranges. The first phosphor wheel generates red light while the second phosphor wheel generates green light, eliminating the need for a cascaded color wheel and achieving both structural simplification and color saturation improvement.
Solution Approach 2:
Each phosphor wheel is designed with specific local properties - the first phosphor wheel uses phosphor materials optimized for red light emission, while the second phosphor wheel uses phosphor materials optimized for green light emission. This localized optimization allows each wheel to excel at its specific function without compromise.
2Illumination intensity
If a color wheel is placed in cascade with the phosphor wheel to achieve acceptable colorimetry, then color saturation is improved, but the mechanical spinning imposes limitations on color switching speed
Solution Approach 1:
The patent replaces the mechanical color wheel with an electronically controlled system using two independently controllable phosphor wheels. This substitution eliminates mechanical spinning limitations and enables faster color switching through electronic control of phosphor excitation, while maintaining high color saturation through optimized phosphor materials.
3Illumination intensity
If a mechanical color wheel spins to cycle through colors, then colorimetry is achieved, but brightness is reduced due to spoke time (transition time between colors)
Solution Approach 1:
The patent implements continuous color generation by using two phosphor wheels that can operate simultaneously or in rapid succession, eliminating the transition gaps (spoke time) inherent in mechanical color wheels. This continuity ensures that useful light output is maintained throughout the entire cycle, maximizing brightness while achieving accurate colorimetry.
4Illumination intensity
If a mechanical color wheel is used to cycle through colors, then colorimetry is achieved, but visual artifacts appear due to limited color cycling rate
Solution Approach 1:
The patent replaces the mechanical color wheel with an electronically controlled dual phosphor wheel system that can switch between colors instantaneously. This eliminates the limited color cycling rate of mechanical systems, preventing visual artifacts while maintaining accurate colorimetry through precise electronic control of phosphor excitation timing.
5Use of energy by moving object
If phosphor materials are used to convert blue laser light, then red and green light are generated, but quenching occurs and deeper reds cannot be produced
Solution Approach 1:
The patent segments the red light generation function into two components: the first phosphor wheel generates red light through phosphor conversion, while the red laser directly provides deeper red wavelengths. This segmentation allows the system to overcome phosphor quenching limitations and produce deeper reds by combining phosphor-generated red with direct laser red.
Solution Approach 2:
The patent uses a composite approach combining phosphor materials with specific laser sources. The first phosphor wheel uses phosphor materials converted by blue laser, supplemented by a red laser to extend into deeper red wavelengths, creating a composite light source that overcomes the limitations of phosphor materials alone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dual phosphor wheel system mitigates quenching, improves red light production, reduces spoke time, and increases color cycles per video frame, leading to enhanced brightness and color performance in video projection systems.
Implementation Method 1
the first phosphor configured to convert the second blue light to longer wavelengths that includes second red light
Implementation Method 2
the second phosphor configured to convert the third blue light to respective longer wavelengths that includes green light
Implementation Method 3
a first dichroic mirror; a second dichroic mirror... the second dichroic mirror is further configured to direct the second red light to the at least one light integrator and transmit others of the longer wavelengths
Data Source
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AI summary
A dual phosphor wheel projection system is provided. A first dichroic mirror directs blue light from a first blue laser to a second dichroic mirror which directs the blue light to at least one integrator. The first dichroic mirror directs blue light from a second blue laser to a first phosphor/ phosphor wheel, which converts the blue light to longer wavelengths that includes red light. The second dichroic mirror directs the red light to the integrator and transmit others of the longer wavelengths. The integrator combines the red light with red light from a red laser. A third dichroic mirror directs the red light from the red laser to the integrator and directs blue light from a third blue laser to a second phosphor/phosphor wheel, which converts the blue light to respective longer wavelengths that includes green light. The third dichroic mirror transmits the green light to the integrator.